Field of the Invention
This invention relates to a connecting shaft including interconnected multiple shafts and a manufacturing method of the connecting shaft.
Description of the Related Art
Conventionally, as a shaft of this type is known one comprising an end joint, an FRP cylinder whose inner peripheral surface fits over part of a serrated portion formed on an outer peripheral surface of the end joint, and an outer collar connecting the end joint and the FRP cylinder. In the shaft described in Japanese Unexamined Patent Publication (JP2014-222069A), for example, the outer collar has a small-diameter portion whose inner peripheral surface fits over a remaining part of the serrated portion and a large-diameter portion whose inner peripheral surface fits over an outer peripheral surface of the FRP cylinder, and the inner peripheral surface of the large-diameter portion is adhered to the outer peripheral surface of the FRP cylinder by adhesive.
However, in the shaft described in JP2014-222069A, the axial direction end face of the large-diameter portion of the outer collar in the adhered state is exposed, so that adhesive strength is degraded by rust invading at the interface between the inner peripheral surface of the large-diameter portion and the adhesive.